A resin-sealed semiconductor device is widely used. The resin-sealed semiconductor device seals a semiconductor chip with resin.
In some cases, a chip component, which is a passive element such as a capacitor or a resistor, is provided in addition to a semiconductor chip in a resin-sealed semiconductor device.
A mounting portion may be formed between lead terminals extend portioning in parallel to each other, in order to mount a chip component. The chip component is mounted on the mounting portion with a conductive paste interposed in between. The chip component is fixed to the lead frame by heating the conductive paste to a curing temperature.
The conductive paste is a mixture of silver filler and epoxy resin, for example. When the conductive paste is thermally cured, the conductive paste may crack due to thermal stress caused by a difference in thermal expansion coefficient between the chip component and the lead frame.
Furthermore, when epoxy resin is prepared for the conductive paste and is cured, the cured epoxy resin may be embrittled with exposure to a high temperature. It may result in causing reduction in adhesion performance and impact resistance.
Japanese Patent Application Publication No. 6-120406 and Japanese Patent Application Publication No. 9-36298 disclose a semiconductor device capable of avoiding generation of thermal stress during curing.
The semiconductor device disclosed in the former patent publication is provided with a groove or a step as a stress absorber in an inner lead portion of a lead frame on which a chip component is mounted.
The semiconductor device mentioned in the latter patent publication has an extension portion formed in a lead frame. The extension portion extend portions to form a band shape which corresponds to a shape of an electrode of a chip component. The tip of the extension portion functions as a mounting portion to mount the electrode. A narrow-width portion, which has a width smaller than that of the mounting portion, is formed at a base end portion of the extension portion.
Such structures of the semiconductor devices disclosed in the above patent publications allow the semiconductor devices to bear thermal stress when the epoxy resin is cured. However, the semiconductor devices may be insufficient to bear heat or physical impact which is applied after curing. In the semiconductor device, a conductive paste, which fixes a chip component to a lead frame, may be cracked to cause the semiconductor devices to be electrically open. In some cases, the chip component may peel off, which shows poor reliability of the semiconductor devices.